EP300 and Burkitt lymphoma: CREBBP is targeted by inactivating mutations and deletions in FL, BL and GCB-like DLBCL.10, 13, 15, 18 CREBBP associates with EP300, which is itself also mutated at a lower frequency in FL and DLBCL.10, 15 The CREBBP/EP300 complex acts to acetylate multiple lysine residues upon all four histones,43 suggesting that their mutation may have broad effects on cellular phenotypes.